AVS 46th International Symposium
    Applied Surface Science Division Friday Sessions
       Session AS-FrM

Paper AS-FrM8
Synchrotron TXRF Quantification Using Ion Implanted Standards

Friday, October 29, 1999, 10:40 am, Room 6A

Session: New or Improved Surface Related Analytical Techniques
Presenter: J.P. Chang, Bell Labs, Lucent Technologies
Authors: R.L. Opila, Bell Labs, Lucent Technologies
J.P. Chang, Bell Labs, Lucent Technologies
J. Eng, Jr., Bell Labs, Lucent Technologies
J.R. Rosamilia, Bell Labs, Lucent Technologies
P. Pianetta, Stanford University
F.A. Stevie, Bell Labs, Lucent Technologies
R.F. Roberts, Bell Labs, Lucent Technologies
M.A. Decker, Bell Labs, Lucent Technologies
Correspondent: Click to Email
Much of the difficulty in quantification using TXRF has been associated with problems in obtaining suitable standards. The quantification can be very accurate, but the standards to date are difficult to prepare and are not generally available. Ion implantation is often used for quantification of secondary ion mass spectrometry and can be obtained for any element, but the implanted distribution is not well defined at the surface. The technique of implantation through a sacrificial oxide layer has been applied to create TXRF quantification standards. Ion implants of Ca, Fe, Cu, Ni, As, and Sb were made through 0.1 µmm SiO@sub 2@ on Si substrates. Measurements were made using conventional and synchrotron TXRF after removal of the oxide. The results show that there is a direct correlation between the ion dose and the TXRF measured dose in the sampling depth for TXRF. Measurements were made using surface and time-of-flight SIMS, with similar conclusions. Certain elements, e.g., copper, are known to plate on the surface after oxide etch. One unique advantage of performing TXRF at the synchrotron is the ability to easily change the energy of the exciting x-rays. Using the dependence upon incident photon energy it is possible to collect a near edge absorption spectrum of the metallic species. This near edge spectrum then permits determination of the chemical bonding of the metallic element. By varying the angle of the incident x-rays above and below the critical angle, the difference in states between an impurity at the surface versus an impurity in the bulk can be determined. If metal remains on the surface, as suggested by the copper data, the surface copper can be removed. This removal was verified using synchrotron TXRF, XPS, and TOF-SIMS.